The production of ceramic layers by means of thermal spraying is known, for example, from a publication of the US Department of Defense (The AMPTIAC Newsletter, Spring 2002, Volume 6, No. 1). According to that publication, microparticles containing the ceramic components of the ceramic coating which is to be generated can be sprayed onto the surface that is to be coated in a thermal spraying process. The thermal spray gun generates a plasma jet into which the microparticles of the ceramic material are injected and are at least partially fused thereby. As a result of this, when the microparticles impact the substrate which is to be coated or the layer that is being constructed, a ceramic structure forms which is optionally finished by means of thermal aftertreatment.
A new class of ceramic materials has recently been developed, namely polymer ceramics. It has been explained with regard to this new ceramic class, e.g. by the chair of glass and ceramics at the University of Erlangen on the internet page www.presse.uni-erlangen.de\Aktuelles\Kerm%20Material.html (available on Jun. 9, 2004), that polymer ceramics cannot be produced using the traditional method of high-temperature annealing (sintering) of raw materials in powder form, because the ceramic raw materials (precursors) as polymers exhibit too great a thermal sensitivity for this method. Instead, it is necessary to pursue a method approach which is largely shaped by chemical techniques, in which the silicon-containing synthetic materials, which are also called pre-ceramic polymers (e.g. polycarbosilanes, polysilazanes and polysiloxanes), are converted into high-performance ceramic materials by means of thermal decomposition (pyrolysis). However, thermal spraying methods cannot be used for the production of polymer ceramics due to the lower process temperatures.
According to O. Goerke et al in “Ceramic coatings processed by spraying of siloxane precursors (polymer-spraying)”, Journal of the European Ceramic Society 24 (2004), 2141-2147, it is known to deposit the precursors of polymer ceramics either as a solution or as molten material by means of spraying onto a surface, on which said precursors then remain adhered. The production of the polymer ceramic is achieved by means of a suitable thermal treatment of the coating which is obtained thus. Firstly, polymerization of the precursors is carried out at 200° C., for example. The sintering treatment for producing the ceramic can then take place at up to 1000° C.
Furthermore, according to L. S. Schadler et al in “Microstructure and Mechanical Properties of Thermally Sprayed Silica/Nylon Nonocomposites”, Journal of Thermal Spray Technology, Volume 6 (1997), 475 to 485, it is possible to produce composites consisting of polymers and ceramic particles by means of thermal spraying (HVOF spraying). For this purpose the thermally sensitive polymer material is processed as particles which are covered by the ceramic material that must be embedded. These particles can be introduced into the flame jet of the thermal spraying method such that the desired polymer-ceramic composite is produced in the sprayed layer.